Catherine Sykes, a clinical scientist, presented current findings from the ongoing EoE  "SWALLeOeW" study.

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The study investigates how the oesophagus functions when a food bolus is swallowed  and evaluates the use and acceptability of physiology testing for Eosinophilic Oesophagitis (EoE). Catherine discussed the study's aim, locations, methods, and emerging insights.

A food bolus is a chewed mass of food mixed with saliva, prepared for swallowing and digestion. This process requires coordination between the tongue, teeth, and salivary glands to ensure smooth passage from the mouth to the oesophagus.

About the Study

The SWALLeOeW study aims to understand the use and acceptability of physiology testing in EoE, a condition characterised by inflammation of the oesophagus. Conducted at University College Hospital and County Durham and Darlington NHS Foundation Trust, the study recently expanded to include participant identification sites in York, North Tees, and Hartlepool. These sites feed into the main centres at County Durham and Darlington.

How EoE is Diagnosed

EoE is typically diagnosed through an endoscopy, a procedure using a camera to examine the oesophagus.

The oesophagus may show signs of narrowing, rings, or trachealisation, though it can sometimes appear normal.

In such cases, a biopsy is performed to detect eosinophils, white blood cells not normally found within the oesophagus. 

A diagnosis of EoE is confirmed when eosinophils are present alongside symptoms such as difficulty swallowing, food getting stuck, or chest pain, then a diagnosis of EoE can be made.

Learn more about EoE symptoms from our community members.

EoE Treatments

There are several treatments available for treating EoE. These include going on a food-elimination diet, taking proton pump inhibitors (PPIs), taking topical steroids, and, in some cases, physical dilatation if there is evidence of narrowing within the oesophagus. 

Most patients achieve histological remission (a reduction in eosinophils to normal levels), though some may continue to experience symptoms. This raises questions about whether the oesophagus functions properly during eating and drinking, which the SWALLeOeW study aims to address.

Tests Used in the SWALLeOeW Study

High-Resolution manometry test

High-resolution manometry measures oesophageal pressure to assess peristalsis—a coordinated squeezing motion that moves food from the top of the gullet into the stomach.

In the SWALLeOeW study, this test is conducted before and after treatment to provide real-time insights into swallowing and symptom patterns.

A thin tube with pressure sensors is inserted through the nose into the oesophagus, creating a pressure map that shows squeezing contractions. 

Red areas indicate strong squeezing contractions, while green and blue areas show weaker contractions. At the top of the map, the muscle at the top of the gullet displays a strong contraction (red), which fades during swallowing to allow food or drink to pass into the oesophagus. A contraction wave follows behind the food, pushing it down towards the stomach. 

By analysing these pressure maps, researchers assess how the oesophagus functions during eating and identify changes pre- and post-treatment.

Pressure map, presented by Catherine Sykes

24-hour pH impedance test

The second part of the study involves a 24-hour pH impedance test, which uses a fine tube, thinner than a piece of spaghetti, inserted through the nose and into the oesophagus. While noticeable, most participants continue normal activities like eating, drinking, and sleeping.

The test measures reflux and other functions within the oesophagus and examines how inflammation changes with treatment. 

Qualitative Interviews

The final part involves qualitative interviews to explore people's experiences.

Using semi-structured interviews, researchers ask specific questions but encourage participants to share freely. This approach helps understand how acceptable the tests are for people with EoE and explores their long-term experiences living with the condition.

Researchers use iterative analysis, adjusting interview questions based on emerging patterns in the data.

Key Concept: Diagnostic Clarity

Catherine highlighted the concept of diagnostic clarity, which reflects patients' experiences before, during, and after receiving a diagnosis.

Pre-diagnosis: Participants expressed fear of severe conditions like cancer or normalised symptoms ("Everyone gets that when you eat fast") and delayed seeking help.

Diagnosis: Reactions often focused on what the diagnosis was not (e.g., "All I took from the report was it's not cancer.") rather than what it was, leading to feelings of relief or validation.

Post-diagnosis: Having a diagnosis helps patients explain their condition and engage with others, easing social ( "...I've been "able to reach out and say, I'm sorry I haven't been in touch or I didn't go to X event, but this is why."), and emotional ( "People made me think it was "mental.") challenges.

Participants also receive clinical reports from their tests, providing insights into oesophageal function, motility, inflammation, and reflux. These reports offered clarity and helped challenge assumptions, such as the belief that EoE always involves acid reflux.

One participant shared: "I said, 'I don't have acid reflux.' He said, 'Well, you will have.' We've since proven that was wrong."

Current Findings from the Study

Recruitment Progress

The research has both quantitative and qualitative aspects. It is too early to draw any conclusions from the quantitative side, as sufficient participants are needed to identify patterns or make conclusions from the data. An important outcome currently is recruitment, as this is a feasibility study aimed at identifying barriers to the research.

To date, 30 patient information sheets have been distributed, with 11 participants enrolled and 6 in prescreening. Seven interviews have been conducted, and six participants have completed the full study. Partial completions occurred due to factors like opting out of specific tests or difficulty tolerating repeat procedures.

Looking Ahead

The SWALLeOeW study is ongoing, with recruitment expected to continue through 2025. Catherine emphasised the importance of working with a patient public involvement group to ensure the findings are interpreted holistically and reflect diverse perspectives.

The study aims to refine diagnostic pathways and improve the patient experience for those with EoE.

Find this study in the UK Clinical Trial Registry using the number ISRCTN17786884 or click here.

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